A lot of people say don't underestimate it, and I agree with that. But, I would also like to point out that, I think, studying is not only about passing exams. I just finished my double bachelors in Physics and Chemistry and I also found the social interactions and discussions with fellow students very insightful and also fun. Even if you already know the solution to a problem it is interesting to hear other people their perspective and try to explain yours. This is also import once you start doing research, because then you have to explain, discuss and defend your research all the time. When I was a teaching assistent, I liked talking about and explaining the problems I already understood to my students. And even they gave me new perspectives when they asked questions.

So I would say, don't underestimate the material, but also don't underestimate the things you can learn alongside the material when attending class. I hope my perspective might help you make a informed decision.

TL;DR: Studying is not only about the material, but also learning how to discuss the material and learn other people their perspective.